1. Field of the Invention
This invention relates to an improvement of a wiper blade rubber.
The wiper blade rubber is an elongate member integrally comprising a thick base portion, a swing portion generally of a trigonal cross section, a neck portion connecting the base portion and the swing portion and a thin plate-like lip portion disposed at the bottom end of the swing portion, and it is used as a wiping member of a wiper. The wiper blade rubber moves slidably along the glass surface of a front glass of an automobile or the like and serves to remove water droplets on the surface of the glass by the sliding movement.
2. Description of the Prior Art
Conventionally, in order to obtain a wiper blade rubber, an unvulcanized rubber material, which is previously blended, has been molded in a metal die to be vulcanized and then the surface of the resulting rubber has been treated to reduce the sliding resistance thereof in accordance with requirement. As the aforesaid surface treatment, for instance, a method of hardening the surface of the wiper blade rubber by chlorination or a method of coating to form a surface layer containing fine lubricating powder such as of molybdenum disulfide on the surface of the wiper blade rubber. However, although the chlorinating method has an advantage of reducing the sliding resistance, it lacks in the wear-resistance. On the other hand, while the method of forming the coating layer containing fine lubricating powder involves a problem in that the coating layer is peeled off during a short period of use and lacks in durability.
Further, an attempt for improving the sliding movement characteristic of the wiper blade rubber by decreasing the frictional coefficient between the wiper blade rubber and the glass surface brings about problems in that the wiper blade rubber does not swing at the neck portion but the swing portion and the lip portion of the wiper blade rubber move slidably while remaining tilted in one direction.